碘-罗丹明B-OP体系分光光度法测定水中溶解氧

基于I3-与罗丹明B在OP存在下结合成电中性的离子缔合物在360 nm波长处有最大吸收,提出了水样中溶解氧的光度法测定。于待测水样中加入硫酸锰及碱性碘化钾溶液,水中溶解氧与之形成Mn2O3沉淀,加入浓硫酸使与Mn2O3沉淀反应而析出单质碘,在酸性条件下析出的碘与罗丹明B溶液在360 nm波长处有最大吸收,以碘酸钾为基准物,对水样中溶解氧含量进行分光光度法测定。溶解氧浓度在0.002 7~0.686 mg/L范围内符合比尔定律,表观摩尔吸光系数为4.012×104L.cm-1.mol-1,方法的检出限为0.001 0 mg/L。此法对不同来源的水样中溶解氧含量进行测定,所得结果与碘量法及溶解氧测定仪所测得的结果相符合。     

制氧同步电动机励磁控制系统消化吸收

介绍首钢集团总公司制氧厂3万m3氧气系统大功率同步电动机西门子PLC励磁控制系统的的硬件及网络构成,解读系统控制程序并整理出控制程序结构和程序块功能,了解大功率同步电动机励磁调节原理和大功率同步电动机起动条件及起动过程。在此基础上建立同步电动机起动及励磁的西门子PLC硬件仿真系统,通过对西门子硬件仿真系统研究和实际运行调试监测,掌握同步电动机的异步降压起动和同步电动机励磁调节实现。根据实际运行系统和硬件仿真系统调试运行的报警和故障信息,总结了大功率同步电动机报警和故障的处理措施及解决办法。     

转炉汽包水位分段模糊控制算法

转炉汽化冷却系统中,控制核心是汽包水位的控制.分析了传统双冲量及三冲量控制方法不能满足转炉汽包水位控制的原因,并针对转炉生产的特点,提出了一种结合转炉生产状态的分段式控制方法,其主吹氧阶段采用模糊控制算法实现对汽包水位的控制.将汽包水位和水位变化率进行模糊化计算,将模糊化计算的结果,作为汽包补水流量调节系统的输入,动态设定给水流量,以达到最终稳定汽包水位的目的.     

PLC在制氧机板式切换控制系统上的应用

广东省韶关钢铁集团有限公司（以下简称韶钢）１号制氧机是６０年代投入使用的日本产１５００ ｍ~３／ｈ机组,空分板式切换系统采用电动凸轮控制系统,已使用３０年．由于长期连续工作,设备老化,凸轮严重磨损,时序无法控制,故障点多,且无替代的备品备件．针对这种情况,为了确保１号制氧机组能够稳定、可控、正常地运行,决定对该制氧机空分板式切换系统进行全面改造,由可编程控制器ＰＬＣ替代电动凸轮控制系统．改造后的系统,完全满足生产工艺要求,达到了较好的效果．１ 控制系统功能及工艺控制流程１．１ 控制系统的构成及功能分…     

An intelligent control system for ventilators

This study reports on a ventilator system that consists of several intelligent modules for controlling ventilator operation. These modules are software programs in two controllers. One controller is a personal computer used for diagnoses, determining settings and checking the effects of settings. The other controller is a single-chip microprocessor in a ventilator that controls the ventilator's settings in accordance with the computer settings. After setting up the system, an artificial lung model simulating a patient's lung is used to test the system. The result of test run indicated that it always responds to a patient's lung condition in a stable manner. Thus, the proposed system with its intelligent modules may assist clinicians in caring for patients and managing ventilator operation.     

An improved snare system for the nonsurgical retrieval of intravascular foreign bodies

We have modified a snare technique originally described for transcolonoscopic removal of colonic polyps for the retrieval of intravascular foreign bodies. The key difference from other snare techniques is the employment of a wire snare with a crimp in its midportion that enables the formation of a loop in a plane perpendicular to the axial direction of the guiding catheter. With this technique we have quickly removed a variety of objects from the right heart and pulmonary arteries in four patients.     

An improved electrogastrographic system in measuring myoelectrical parameters

This study assessed the reliability of an improved electrogastrographic (EGG) system in recording stomach myoelectrical parameters and tried to establish the normal ranges of myoelectricity using this system. The analytical software of the current system mainly included an autoregressive modelling program to compute myoelectrical frequency and power. Forty healthy subjects were enrolled to receive myoelectrical measurement in two consecutively fasting and one postprandial 30 min sessions. The myoelectrical frequencies in both fasting and postprandial sessions were almost three cycles per min (c.p.m.) and showed little variation. The percentage of dominant frequencies (2.5-3.5 c.p.m.) in three sessions was approximately 80% while the computed myoelectrical powers in the first and second fasting sessions exhibited a significant correlation (r=0.84, P<0.001). Meal ingestion increased the myoelectrical powers by 6.8dB compared with the second fasting recording (P< 0.001). The mean variation in myoelectrical amplitude for the ratio of second: first fasting session was 110.3+/-88.8% (16-478%, median 88%). This new EGG system is, indeed, reliable for measuring myoelectrical frequency and power, whereas the interassay of recorded amplitudes appears markedly variable.     

RH炉多功能氧枪系统控制

为满足某大型钢厂引进的RH炉的控制要求,开发了RH炉控制系统。系统包括基础自动化、供配电、监控和网络系统。其中,多功能氧枪控制是基础自动化系统的核心部分,采用变频器完成氧枪的驱动控制,PLC完成设备的逻辑控制。系统投产至今,运行稳定,控制功能良好,满足了超低碳钢钢水的各项工艺要求。本文重点介绍RH炉多功能氧枪的基本结构,控制系统构成,氧枪主要功能、控制流程等,并给出了控制指标。     

制氧生产的自动变负荷控制

从转炉生产与氧气生产的关系,说明采用制氧生产自动变负荷控制的意义,并阐述自动变负荷系统的原理,控制参数和调节周期。分析自动负荷采用系统运行中的问题及应采取的措施。     

半浮芯棒连轧管机自动控制系统

衡阳钢管厂半浮芯棒连轧管机是国内引进的首套具有当今世界先进水平的半浮芯棒连续轧管机组，其自动控制系统是由计算机，ＰＬＣ，控制器构成。投运以来，系统运行稳定可靠，控制精度高，钢管质量好，取得了预期效果。     

Effect of dissolved oxygen on the surface tension of liquid iron

Abstract

The oscillating drop technique was used to measure the surface tension of liquid iron-oxygen alloys in the temperature range 1560–1645°C. No noticeable temperature dependence of the surface tension was observed. The surface activity of oxygen in iron was determined to be 2.1 × 10⁶ dynes/cm. This value is twice as large as the accepted value in the literature. According to the monolayer approximation, the liquid iron surface becomes saturated with oxygen when each adsorbed oxygen atom occupies an area of 11.4 Ų. Data-analysis suggests that saturation of the surface of liquid iron with oxygen results from the formation of a two-dimensional ionic compound. This compound seems to correspond to Fe₂O or FeVO, where V stands for a vacancy.

Résumé

La technique de la goutte oscillante a ét é employ ée pour mesurer la tension superficielle des alliages liquides fer-oxyg ène entre 1560°C et 1645°C. Aucune variation de la tension superficielle avec la temperature n'a été observée. L'activité suferficielle de l'oxygéne dans le fer a été établie comme étant 2.1 × 10⁶ dynes/cm. Cette valeur est deux fois celle admise dans la littéature. Selon l'approximation d'une monocouche, la surface du fer liquide sera saturée d'oxygé ne quand chaque at orne d'oxygene absorbe occupe une superficie de 11.4 A². L'analyse des données indique que la saturation de la surface du fer liquide par l'oxygéne résulte de la formation d'un composé ionique bi-dimensionnel. Il semble que ce compose corresponde à Fe₂O ou FeVO, ou V est une lacune dans le réseau.     

An automatic infusion system for the measurement and control of uterine activity

23-day-old male rats were left intact, rendered blind and anosmic, pinealectomized together with blinding and anosmia, or subcutaneously implanted with graded doses of melatonin in beeswax immediately following surgical blinding and anosmia. 5 weeks later, blind, anosmic animals were found to have significantly depressed anterior pituitary, testicular, and accessory sex organ weights. Both pituitary and plasma prolactin and luteinizing hormone (LH) concentrations were also significantly suppressed. Pinealectomy of blind, anosmic animals completely restored testicular and accessory organ weights. Likewise, pituitary LH and prolactin and plasma LH levels were also restored to intact control levels by pineal removal. Only the highest dose of melatonin (1 mg) restored the testicular and accessory sex organ weights to those of the intact controls. As little as 1 microgram melatonin restored plasma and pituitary LH concentrations to the levels of the intact controls. However, none of the dosages of melatonin reversed plasma prolactin concentrations to those of the untreated animals. The decrease in pituitary prolactin induced by blinding and anosmia was reversed by pinealectomy or by the lower doses (1, 50 or 100 micrograms) of melatonin. These results indicate that melatonin can reverse the antigonadotrophic effects of blinding and anosmia in male rats. The minimal dose of melatonin required to restore testicular and accessory sex organ weights in blind, anosmic rats is 1 mg implanted subcutaneously in beeswax.     

智能钢包精炼炉控制系统

介绍一种钢包精炼炉智能控制系统。给出此系统的主要功能和系统结构,重点介绍基于复合人工智能技术的热平衡计算和钢水温度预报、能量输入动态优化和智能电极升降控制,最后给出现场应用结果。     

Effect of arsenic on the activity of oxygen dissolved in dilute liquid copper solutions

The influence of arsenic additions on the activity of oxygen in liquid copper was studied by the solid-electrolyte galvanic cell (−) Pt, W/Cu-O-As ∥ ZrO₂-CaO ∥ NiO-Ni/Pt (+) in the temperature range 1373 to 1473 K. The activity coefficient of oxygen in liquid copper was found to be unaffected by the addition of arsenic. The interaction parameter values for group V B elements in the periodic table with respect to oxygen are discussed in the light of the solute interactions in copper. H. Walqui, Formerly on leave at the Department of Theoretical Metallurgy, The Royal Institute of Technology     

Mathematical model for nitrogen control in oxygen steelmaking

A mathematical model was developed to quantify the effects of different operational parameters on the nitrogen content of steel produced during oxygen steelmaking. The model predicts nitrogen removal by the CO produced during decarburization and how the final nitrogen content is affected by different process variables. These variables include the type of coolants used (scrap, direct reduced iron (DRI), etc.), the sulfur content of the metal, combined gas blowing practices, and the nitrogen content in the hot metal, scrap and oxygen blown. The model is a mixed control model that incorporates mass transfer and chemical kinetics. It requires a single parameter that reflects the surface area and mass-transfer coefficient that is determined from the rate of decarburization. The model also computes the rate of decarburization and the change in surface active elements, such as sulfur and oxygen, that affect the rate of the nitrogen reaction. Nitrogenization of steel in the converter is also predicted with the model. The computed results are in good agreement with plant data and observations.     

中型轧钢厂加热炉自动控制系统

介绍了安钢中型轧钢厂加热炉计算机控制系统的结构和功能，阐述了将数学模型应用于加热炉燃烧过程控制的情况和特点。实时控制结果表明：该系统是可行的，取得了满意的控制效果。